Two full 4ml EDTA tubes required.
Samples should not be visibly haemolysed.
Up to several weeks.
Samples are batched due to high overseas transport costs. Urgent requests are considered only in exceptional circumstances and must be individually justified.
Roche (sandwich) immunoassay
Results using this assay are not necessarily comparable to other methods. Serial results should be followed by the same method and laboratory.
Transport at 2-8C and centrifuge within 6 hours. If transport to LabPlus is delayed, separated plasma samples should be kept frozen.
Requesting details (IMPORTANT)
The Florey Institute request form must be completed (see pdf attachment). The form should be printed and completed by an approved requestor, then imaged and emailed to chemicalpathologist@adhb.govt.nz . If the form is not fully and correctly completed then the sample cannot be processed and sent to Florey. The form should be emailed before the patient is sent to the lab depot for testing, All requests are vetted by LabPlus chemical pathologists.
When the patient presents to the depot, the request for "neurofilament light (NFL)" and "send to LabPlus" must be clearly written in the additional tests box.
This test is only available when requested or endorsed by neurologists. Other specialists such as psychogeriatricians, metabolic physicians or psychiatrists specialising in cognitive decline will be approved on an individual basis.
Testing implications for the patient and family should be carefully considered and discussed with the patient and/or caregivers prior to requesting. It is the responsibility of the clinician to obtain informed consent. If the patient is unable to give informed consent then it must be obtained from close family members with due authority as parent or guardian, or power of attorney.
Download: Florey Institute Request Form - Plasma p181 and NFL - Florey Institute Request Form.pdf
Interferences
Haemolysis may give false low results. Affected samples will be rejected and not sent to Florey Inst for testing.
Recent intake of high dose biotin (>5mg/day) may affect results; biotin should be stopped for at least 8hours prior to testing, and preferably at least 2-3days if much higher doses, prior to testing.
Renal disease may cause false elevation, related to the decline in GFR (see details below)